1. Field of the Invention
The present invention relates to a safety bracket for use with monorail systems, and more particularly to a safety bracket that fully supports and retains a vehicle on the monorail without the vehicle becoming fully separated from the monorail.
2. Statement of the Problem
Monorail systems typically include a monorail, a number of vehicles that move along the monorail and electronic control systems that control the movement of the vehicles along the monorail. Typically, the monorail has both straight and curved sections. The monorail is an industry standard aluminum and/or steel rail having an I-type cross section. At the largest dimensions one embodiment of the I-beam has a cross section of about 180 millimeters by 60 millimeters. This dimension allows the monorail (aluminum) to support up to about 1200 kilograms. In most applications, the monorail is installed on overhead support beams or suspended from the ceiling. This overhead configuration allows the vehicles to move along the monorail and perform tasks without being impeded by obstacles located at the floor level.
The electronic control system is used to instruct the vehicle to move along the monorail and to perform predetermined tasks. The electronic control system includes a system controller that communicates with to the vehicles. The system controller is programmed by an operator to instruct the vehicle to move along the monorail and perform predetermined tasks.
The vehicle includes a trolley and a load portion. The trolley includes mechanisms that are used to drive, suspend and align the vehicle on the monorail. However, in an "inverted" monorail configuration, the load portion is positioned above the monorail. In this regard, the trolley includes a motor attached to wheels that drive the vehicle. Typically, the drive wheels contact a top of the monorail. Guide wheels are also connected to the trolley and positioned along the sides of the monorail to align the vehicle on the monorail.
The load portion of the vehicle is attached to the trolley and is typically positioned below the monorail. Further, the load portion is attached to the trolley such that the load portion can pivot with the trolley as the vehicle moves along the monorail. This type of attachment typically includes a shaft that is attached to the load portion and rotatably secured in a pivot hole located in the trolley. This pivoting is desired when the vehicle maneuvers around curved sections of the monorail.
Typically, the trolley is composed of an aluminum alloy casting and is capable of carrying load of over 400 kilograms. These loads induce high stresses and strains on the trolley during operation of the monorail system. From time to time, manufacturing and other problems occur that cause the trolley to become separated from the monorail during operation. In this regard, the vehicle may encounter obstacles on or off the monorail or be maneuvered improperly causing the trolley to become disengaged from the monorail.
In an attempt to prevent the trolley from becoming completely separated from the monorail, conventional systems use a cable to fixedly attached the load portion to the trolley. Therefore, in the event that the shaft connecting the trolley to the load portion fails, the load portion remains connected to the trolley. However, the cable cannot be completely wrapped around the monorail because the cable interfered with movement of the vehicle and with components that are attached to the monorail. Therefore, this technique does not prevent the trolley of the vehicle from becoming completely separated from the monorail.
Therefore, a need exits for a mechanism that prevents the trolley of a vehicle from becoming completely separated from the monorail. Also a need exists for a mechanism that securely supports the vehicle on the monorail if the trolley becomes separated from the monorail.